Prince William County’s GIS offers new features for users

The Prince William County Geographic Information Systems (GIS) Office is responsible for creating and maintaining the county’s spatial information.

GIS updates its aerial photos every two years, and the latest photos covering the county were just taken earlier this year.

The office offers everything from interactive mapping to maintaining the county’s street and subdivision lists to archiving aerial photos from 1937 to present day.

Updating aerial photos is critical to providing correct and useful information to the County’s residents. The photos, used in conjunction with GIS software, can help residents find the nearest park, school, library, commuter lot, or police and fire and rescue stations, in addition to locating election precincts and voting places, streets and plats for a given property.

GIS Systems Developer, Malcolm Echaluce, said the new aerial photography includes Quantico Marine Corps Base and its immediate surroundings, which were not included in past aerial surveys due to homeland security constraints. “The aerial photography we’ve got for this year pretty much covers every square inch of this county.”

The photos also show latest development across the county. “The newer aerial imagery we have now will enable you to get a better picture of what the county looks like now,” Echaluce said.

In addition to having new photos, the county’s GIS Office now provides GIS data that is compatible with Google Earth. “It’s a file format of our GIS data that people obtain and use in Google products. For instance, they can import it into Google Earth, so if they wanted a GIS layer of our streets, they’re able to get it in a format for Google,” said Echaluce.

Echaluce said the new format, which allows people to use Google products, will make GIS analysis easier for people who don’t have a full GIS software suite. “People are used to using Google tools. Since people are most familiar with Google mapping products like Google Maps and Google Earth … having that new data format will reach a new audience.”

The County Mapper XM, which is the county’s most popular GIS web tool, is an interactive application that gives users the ability to query properties by their parcel identification number or address. Users may select and use any of the new images with the various data layers.

Visit the GIS Office website at for more information or call 703-792-6840.